This is highly intriguing, and it would be an interesting follow up to see if the opposite was true. If they read a passage on people helping each other, and one version said "The Lord commanded Israel to take their brothers in their arms and comfort them before the LORD," would the people who were commanded by god to be good be any less violent?

And since the bible contains conflicting messages (god loves everyone, but smites people who upset him) how might people's aggression levels correspond to similar passages?